Passageways, in particular for high-speed rail vehicles, are sufficiently known from the prior art. The passageways typically comprise two bellows, wherein the bellows encompass, in a box shape, a passageway bridge between the two carriages of a rail vehicle. A bellows construction of this type is “pressure-tight”; by “pressure-tight” one understands it to mean that when a bellows, over the course of a certain time period, is subjected to an excess of pressure, or a negative pressure, respectively, the pressure is not allowed to fall below or climb above a certain value, with respect to time.
It is known that when entering a tunnel, particularly when two trains meet in a tunnel, considerable pressure surges occur. Measurements in this context have shown that, in extreme cases, pressures of up to many kilopascals are applied to the outer surface of the train, and of course, in this respect, to the passageway construction having the bellows, when two trains meet in a tunnel at the midpoint of said tunnel. Once the two trains have passed each other, a negative pressure occurs in the range of likewise many kilopascals. As a result, very considerable deformation occurs in the region of the bellows, wherein it has been established that the outer bellows is deformed radially by a pressure surge of this type to the extent of approx. 20 cm inwards and outwards. When deformed to such a degree, the bellows frames reach their yield point in certain circumstances, i.e. they potentially arrive at the point of plastic deformation. This means that in adverse circumstances it may occur that the bellows frames may be damaged when subjected to recurring loads. The reason for the extreme deformation of the outer bellows, both by an excess of pressure, as well as with a negative pressure, with respect to the inner bellows, rests substantially on two factors. The first factor is that the outer bellows is substantially larger than the inner bellows. With high-speed trains it is becoming increasingly more common to connect the outer bellows between the two vehicles such that it is flush with the outer surface of said. In contrast, the inner bellows exhibits a relatively substantially smaller radial expansion. The result of this is that the outer bellows exhibits a significantly larger surface area than the inner bellows, which results in the bellows being subjected to a greater degree of deformation. The inner bellows, however, is protected by the outer bellows, such that due to these factors, significantly lower pressures exist in the space between the two bellows, which lead to a deformation of the inner bellows. In this regard, it has been established by measurements that the pressure exerted on the inner bellows amounts to approximately one half of the pressure to which the outer bellows is subjected. This pressure is the result of the deformation of the outer bellows and the resulting change of volume between the bellows. The inner bellows tends to be deformed to a lesser degree for these reasons, due to the smaller surface area and due to the relatively high degree of stiffness as a result of the shorter tangential expansion of the bellows frames having the same cross-section of the bellows frame as that of the outer bellows.
With this background, the invention assumes the objective of minimizing the deformations of the outer bellows that occurs during pressure surges, such as are described above.